Preparing to Use dbcc checkstorage

Before you can use dbcc checkstorage, configure SAP ASE and set up the dbccdb database.

Each action is described in detail in the following sections. The examples in this section assume a server that uses 2K logical pages.

This table summarizes the steps and commands in the order you should use them.

Preparing to use dbcc checkstorage
Action	Use
1. Obtain recommendations for database size, devices (if `dbccdb` does not exist), workspace sizes, cache size, and the number of worker processes for the target database.	use master sp_plan_dbccdb
2. If necessary, adjust the number of worker processes that SAP ASE uses.	sp_configure number of worker processes memory per worker processes
3. (Optional) Create a named cache for dbcc.	sp_cacheconfig
4. Configure your buffer pool.	sp_poolconfig
5. If `dbccdb` already exists, drop it and all associated devices before creating a new `dbccdb` database.	drop database
6. Initialize disk devices for the `dbccdb` data and the log.	disk init
7. (Optional) Create `dbccdb` on the data disk device.	create database
8. (Optional) Add disk segments.	use dbccdb
9. Populate the `dbccdb` database and install dbcc stored procedures.	`isql -Usa -P -i $SYBASE/$SYBASE_ASE/scripts /installdbccdb`

Note: dbcc checkstorage runs its checks against the database on disk. If a corruption exists only in memory, dbcc may not detect it. To ensure consistency between two sequential dbcc checkstorage commands, first run a checkpoint. Be aware that running checkpoint may turn a transient memory corruption into a disk corruption.

Planning Resources
Selecting the appropriate device and size for dbccdb is critical to the performance of dbcc checkstorage operations.
Configuring Worker Processes
The max worker processes, number of worker processes, and memory per worker process configuration parameters affect dbcc checkstorage.
Setting a Named Cache for dbcc
If you use a named cache for dbcc checkstorage, you might need to adjust the SAP ASE configuration parameters.
Configuring an 8-page I/O Buffer Pool
dbcc checkstorage requires a I/O buffer pool of one extent (8 data pages).
Disk Space for dbccdb
Additional disk storage is required for the dbccdb database. Because dbcc checkstorage uses dbccdb extensively, place dbccdb on a device that is separate from other database devices.
Segments for Workspaces
You can control workspace placement and improve dbcc checkstorage performance by using dedicating segments for workspaces.
Creating the dbccdb Database
By default, the dbccdb database is not installed by default; you must create it for dbcc checkstorage can record configuration information for target databases, operation activity, and the results of the operations.

Parent topic: Checking Database Consistency